Allergic conjunctivitis is a disease of the eye that affects millions of people. The symptoms of this disease include itchiness, tearing, and swelling of the eyes. Sometimes this disease is seasonally associated with the spring and summer hay fever seasons, but many people experience symptoms of this disease throughout the year. The symptoms of allergic conjunctivitis are caused and mediated by the binding of histamine to its receptor. Antihistamines are a class of pharmaceutical agent known to either or both suppress the release of histamine from associated mast cells and prevent the binding of histamine to its associated receptors. These agents have been used to treat the symptoms of allergic conjunctivitis and one such agent is ketotifen fumarate. Topical solutions of ketotifen fumarate are currently sold in the United States. The concentration ketotifen in of the U.S. approved ketotifen fumarate formulation is 0.025% (0.25 mg/mL). At that concentration, the recommended dosing regimen is twice daily. It is known that the recommended dosing can be reduced if the amount of ketotifen fumarate is increased, but it is also known that higher concentrations of ketotifen fumarate sting and burn upon initial administration to the eye.
Further it is known that they symptoms of allergic conjunctivitis have a greater impact on the wearers of contact lenses. Many contact lens wearers stop using their lenses during the spring and summer hay fever seasons and other peak allergen seasons. Contact lens wearers can administer topical ketotifen solutions to reduce the symptoms of allergic conjunctivitis. However, if the inconvenience of carrying a bottle of solution can be avoided, it would be beneficial. In addition, since it is known that higher concentrations of the ketotifen fumarate can cause stinging and burning, it would be beneficial if the symptoms of allergic conjunctivitis were alleviated by administering an amount of ketotifen fumarate to patients that did not cause stinging in a dose that lasts longer than 6 hours. These benefits are provided by the following invention.